The present invention relates in general to conveying apparatus for use in transporting mineral ores, especially coal, in mineral mine workings.
It is well known to employ a scraper-chain conveyor composed of channel sections or pans joined end-to-end and a scraper-chain assembly moved along the channel sections, usually in upper and lower runs. In some installations, a conveyor of this type is arranged alongside the mineral or coal face and discharges mineral ore onto another conveyor in a roadway. In other installations, with which the present invention is mainly concerned, a group of straight channel sections is installed in both the mine working or longwall working and the roadway gallery and a curved channel section connects the groups of channel sections together. In such apparatus, it is necessary to provide guidance for the scraper-chain assembly in its passage over the curved section. One form of known guidance device employs discs or wheels rotating about a fixed fulcrum and engaging with the scrapers of the scraper-chain assembly. Examples of known guidance devices are described in the journal Gluckauf 1976, pages 873 to 877, and in German Pat. Nos. 2065424 and 2051384. It has been established in practice that efficient guidance is realized if four or more scrapers engage with the guidance discs or wheels at any one time. This means that with the normal spacing between adjacent scrapers, the diameter of the guidance discs or wheels is considerable and hence the guidance device takes up a relatively large space. The guidance device can be reduced in size if the scrapers are positioned closer together than is normal. However, a scraper-chain assembly with closely-spaced scrapers leads to higher costs and excessive weight. Another problem encountered with known apparatus is that of adequately supporting the roof of the working over the critical region where the longwall and roadway meet, especially where the guidance device takes up a great deal of space.
German Pat. No. 2013089 describes another guidance device wherein rollers are supported for rotation on their inner peripheries and a roof support is accommodated inside a compartment of the guidance device. The present invention has as its object to provide apparatus similar to that described, but improved mainly in respect of the roof supporting function.